Thanks for the encouragement, Watson.
I visited the Elna Heirloom Sewing Machines" Yahoo group and found an uploaded service manual which miraculously covered removal of the thread take up lever.
Here it is now:
[ATTACH=CONFIG]613446[/ATTACH]
Incidentally, is the For Sale section here working? I went to look to see if anyone had a spare one and there doesn't seem to be anything listed at all.