IT IS 10 o’clock on a spring Monday morning, the sun is shining on south London and Laetitia Sadier is preparing for yoga class.

“I need to stretch,” she says, extending the word playfully.

A gentle, optimistic start to the week, then, which is appropriate since the singer who swapped Paris for the English capital almost 30 years ago is touting a new solo album – her fourth – to which both adjectives apply. As might be expected by long-time observers of Sadier’s work – with Stereolab, whom she co-founded with her then partner Tim Gane in 1990, the group Monade and under her own name – Find Me Finding You is silkily assembled, graceful and ultimately uplifting, despite the state of the world in which it was conceived.

Of concern to Sadier, even on this less than manic Monday, are such topics as the western world’s lurch to the right, the dysfunction of democracy and the smothering of alternative culture. There are, however, more personal matters on her mind too, not least the impending departure to university of her and Gane’s 18-year-old son. Sadier sees herself “less and less” as a mother, she explains matter-of-factly. “I’m being made redundant soon,” she says. That will never happen, I tell her, to which she replies, “Thank you for reassuring me.”

Her love of politics and the politics of love have long informed Sadier’s music, and the new record, released under the banner of the Laetitia Sadier Source Ensemble, continues that tradition. Of particular note is the song Love Captive, on which she is joined by Alexis Taylor of Hot Chip and in which she covers a subject that will poke the ribs of many people in middle age and beyond.

“It’s questioning why there’s a sense of belonging and possession in romantic relationships,” she says. “I was questioning if there is a way around it. After a long time with couples there is a lassitude at some point, particularly around sexuality. How do you not live a frustrated life with a partner you kind of owe fidelity to? How do you revive the flame? Most people are confronted by that and it’s hard.

“I haven’t got any solutions, but I wanted to put it out there because it’s important. You don’t need to be married all your life to the same person. You need to learn things and you learn from different people.”

For the record, Sadier and Gane split up in the early 2000s. "Is she in a relationship?" I ask. “No, I’ve been single for two months,” she says. “Why, are you interested?”

Steady on, I reply, steering the conversation hastily towards the contribution of another collaborator on Find Me Finding You, Jeff Parker. The guitarist with Chicago post-rock collective Tortoise co-wrote string arrangements for the record. “He used to be in a band called Isotope 217 and I was a big, big fan,” she says. “Very melodic and strange chords, though when he goes into his doy-di-doy-di jazz guitar I switch off a bit. I wanted the melodic Jeff Parker and he gave me that, so I was very pleased.”

What you won’t hear on the album, however, are string instruments other than bass and guitars. Sadier had the “genius idea” of transposing the arrangements for a small choir which included herself. On a practical level she couldn’t justify the expense of hiring musicians and on a musical level “what I love is voices”. “For strings to sound good you need quite a few players, they have to be very good and the energy has to be very vibrant,” she says. “I couldn’t guarantee I would get the sound I want. I guess I’m fussy.

“I gathered some friends who I know can stand in front of a microphone. It’s hard to sing like that with other people and sing certain parts. I was limited by time but it’s really fun to sing together so that’s how it was done.”

One of those friends is the French musician Nina Savary, who will join the core Source Ensemble trio of Sadier, Emmanuel Mario and Xavi Munoz when they visit Glasgow next week. As Sadier nears the end of her forties, what is her attitude to touring?

“I’m made for it,” she says. “I always get exhausted as soon as I set foot in the van but I like it very much. I feel I’m perfectly suited to the pace. I don’t like long drives. I like to have time to walk in the park, to ground myself – grounding is very important – so the longer the drive the less time you have for that and it can get very” – she makes a sound like a demented wireless – “and your head is spinning.”

As for translating the album’s immaculate confections on stage, Sadier is bullish. “I have very high hopes that we’re going to have something bigger than the sum of the players, and operate some magic,” she says. “I’m confident we will in the sense that the four of us sing together and it’s going to sound pretty nice.

“There’s going to be less drumming – the rhythm is carried through other things. I realised you don’t need drums for rhythm. There’s rhythm in nature, in energy, in waves, and I wanted to explore that on the album.”

Sadier’s allusions to elemental forces and the importance of grounding are far from exceptions to the rule. How does she feel her music can help mitigate the prevailing political mood of the western world?

“I don’t think we can operate a resistance movement because that would lead to even more division, possibly war, and that’s what some people want because it sells weapons – you mustn’t give in to that,” she says. “But I believe you occupy space with your energy, with your vibrations, and that can be contagious, so that’s what I try to put out – the more optimistic point of view. There’s no fate, we can be the determining power of our future.

“That’s my revolutionary angle. It’s about not being completely depressed and beaten and giving in to the populist game.”

Whether in the United Kingdom or France, Sadier believes political systems are in a bad place and can only be rescued by people becoming more involved in them. “We have to be much more responsible in how things are shaped,” she says. “Being engaged as a citizen will build who you are. It’s exciting to be involved. People are disconnected from their role in society, they’re disconnected from nature and they’re disconnected from their own selves.

“It’s clear that we feel happiest and most fulfilled when we make a connection with people. If someone dies it’s important to connect with people who knew that person and it feels good. And when you feel good you vibrate at a higher rate” – she laughs – “and things clear naturally.”

Connecting with her audience, Sadier acknowledges, is harder now than it was during the 19-year lifespan of Stereolab. Does she feel the group were lucky to be most active before the internet all but demolished the independent music scene?

“Extremely so, because nowadays alternative culture is being f***ing stifled in a dangerous way and it worries me. We need independent voices out there and it’s more difficult today. Although there’s the internet and da-di-da all my friends are struggling to find live work.”

Lest you infer that Sadier lives in anything but the moment, you won’t find Emperor Tomato Ketchup or any other Stereolab records on her turntable.

“I don’t look back much,” she adds. “I thought the music was wonderful and it still is and that’s what I take home with me – what a great musical adventure it was.”

The adventure continues, gently.

Find Me Finding You is out now on Drag City. Laetitia Sadier Source Ensemble play CCA, Glasgow, on Monday.