Thanks a bunch. What do you suppose caused this? I knew it was something rather simple but had never accessed the Previous Recipients list before. Glad to have found that as well. When people change their addresses, all of their previous ones come up when addressing an email and this requires some concentration (guessing) to remember which one is correct. So now I can edit those as well. Genius. No, Super Genius!
Oops! Not so fast. Didn't work.
But this did and here's the story. My sister recently moved so I updated her new physical address in Address Book. Somehow, when I did that, my email address became attached to her Card. When I checked in the card in Address Book just now (as you suggested above), there it was. I edited the entry and this solved the problem.
Super Genious status restored.