Artemisia Gentileschi has definitely had a hard time. Although she was an outstanding Renaissance painter in the style of Caravaggio, and the first woman to become a member of Florence’s Accademia di Arte del Disegno, her work was attributed to her father Orazio for centuries.

Armchair theatre-lovers rejoice. During the lockdown, the National Theatre is streaming a selection of its past hits for free for one week at a time. These shows, originally filmed as part of the flagship’s NT Live project (which broadcast beautifully produced recordings of shows to local cinemas nationwide and abroad), are now available on its YouTube channel.

“The whole world is just tilting at the moment,” we’re told near the end of Wild, the Mike Bartlett play from summer 2016 that is available (through Sunday) online to help get us through these wild times right now.

With everyone in lockdown, observing physical if not social distancing, a story about isolation can have a particular resonance. And there are few places in the UK that are as isolated as some parts of the Scottish Highlands. Ali Milles’s tartan gothic thriller, The Croft, is partly a study of the advantages and disadvantages of living in a remote location, and partly a more speculative and suggestive account of how family tragedy repeats itself down the generations.

“Whipped cream with knives” is how Harold Prince, who directed the Broadway premiere of A Little Night Music in 1973, famously described this particular Sondheim show. And nowhere is that borne out with more exquisite agony than in this duet between two unhappily married women.

Ever since I heard the quintessential prog rock group The Nice do a psychedelic instrumental version of “America” in 1968, I have loved this song. Later on, I was better able to appreciate Sondheim’s lyrics, whose satirical sharpness and superb inventiveness make this the definitive song about migration.

Along with many others, my first exposure to Stephen Sondheim’s art was through watching the film of Bernstein’s West Side Story as a child. The song which still floors me is the Quintet near the end of Act 1. Bernstein’s ecstatic, dynamic music is  splendid in itself, but the number’s perfection is sealed by Sondheim’s lyrics, each character distinctly voiced, the rhythms and rhymes flawless. “Sperm to worm,” still makes me grin. That ability to articulate different voices, to overlay disparate musical styles is a trademark.

The way that theatres and other arts institutions have leapt into action over the past week, providing a wealth of material online and new ways to connect with audiences, has been truly inspirational.

Two numbers, one hair-raising slice of music-theatre. When Sondheim's paying homage to the older, revue type of musical, you can extract a string of top hits: Follies, from which Marianka Swain chose "I'm Still Here" yesterday, could yield at least half a dozen more choices, Company almost as many. When his aim is a more through-composed kind of story-telling, with leading motifs recurring and transformed, "highlights" are less easily detached.

It’s only been a week since London’s West End went dark, and theatres closed all over the UK, but it feels like months. Really. Like many, I’m in self-isolation, stressed by working online and worried about getting enough food and essentials, so it is heartening to know that digital performance – can you even call it theatre? – is alive, and, if not exactly live, certainly kicking.