Paddy! Amazing!! I was wracking my brains over this, madly going through every receipt which I summarily tossed into my backpack trying to locate the note I put the info on! I, too, Googled "Lady in Lake," and "Nymph" and "Nymphe" because I recalled something like that with a "y" in it... I didn't recall "Martyre."
Also, the copyright info you linked to seems to be fairly clear -- that any copyright claim has long since expired, and owning the painting in the public domain (the Louvre) does not confer copyright. So it seems that I can use it.
dboh, thanks! That is an interesting question. The paintings are remarkably similar. I'm not knowledgeable in the history of art, but perhaps someone else here can answer it.
Thanks again to all for your help!
Lorraine
P. S. Paddy, yes... Your prize is a free copy of the book! (Don't cry... You don't have to read it!)