All right, this artist may not be obscure to some of you, but I believe the album will be:
St. Giles Cripplegate by Jack Nitzsche with The London Symphony Orchestra.
Neil Young fans will recognize the name Jack Nitzsche from the Harvest album, upon which Nitzsche plays piano and produces a couple of songs. I already knew of him from his work with Phil Spector, for whom he arranged and orchestrated (think of "River Deep, Mountain High"). He was also a songwriter, having written (with Sonny Bono) for example "Needles & Pins", a big hit for The Searchers. He also played piano on a lot of mid-to-late 60's Rolling Stones albums, and then briefly joined Crazy Horse after completing Harvest, playing piano on and producing their great s/t debut album.
Jack got into scoring movies in the 1970's, including Performance and The Exorcist. He also produced some great albums, including Graham Parker's Squeezing Out Sparks and a few for Willy DeVille (a great singer).
St. Giles Cripplegate is 20th Century Classical music, released in 1972 on The Initial Recording Company in England and on Warner Brothers Records in the U.S.A. It was produced by Elliot Mazer, Neil Young's manager. Good luck finding a copy! The only one's I've ever seen are the UK and USA's I have (one of each, with very different covers).