Thanks, everybody, for your suggestions!

I could click on the down arrow next to the little head, but it was essentially grayed out as far as offering me choices of how to log in. Annoyingly, clicking it refreshed the display with a note in red: "this user has disabled anonymous posting."

I tried refreshing the screen, clearing out my cache and cookies, etc. and nothing worked. So I've created a basic LJ profile, and now it recognizes me. Hooray for all of you, because I wouldn't have figured it out myself!