I'm currently listening to Roy Orbison's Mystery Girl. I starting wondering about the writers for "California Blue," so I looked up the publication data. Unsurprisingly, "California Blue" was co-written by Jeff Lynne (along with Roy Orbison himself and Tom Petty). Lynne also produced some of the tracks on Mystery Girl (including "California Blue"), and co-produced the Traveling Wilburys album that Orbison was involved with.
His co-writing this song is unsurprising because a lot of Lynne's songs with Electric Light Orchestra have the word blue in them - "Bluebird is Dead" from On the Third Day, "Boy Blue" from Eldorado, "Mr. Blue Sky" from Out of the Blue, "Midnight Blue" from Discovery, and "Bluebird" from Secret Messages. In the liner notes for Discovery, he says, "I've lost count of the songs I've written with the word blue in the title. I just love the word blue."
So it's interesting that, knowing Lynne's preference for the word and the working relationship that Orbison and Lynne had, you can tell that Lynne had a hand in writing the song just by that one word.
