Update: Yup, the entry is gone. The windows task manager showed two processes not responding, both LJ update pages, but one had the Opera icon and the other was Explorer.exe. I used "end task" on the one with the Opera icon, and they both shut down. I don't know what would have happened if I had used "end task" on the other one. I also don't know what Explorer has to do with Opera.
Anyway, I had opened Firefox to post this entry, and discovered that there was something I could do with it that I didn't know about. There were two over-wide images posted on my friends page. I was about to filter out the users who posted them, but following a hunch, I right clicked them instead and found that Firefox's Adblock extension will block individual images by URL! It knocked them both off the page instantly. Given the frequency with which over-wide images get posted without cuts at LJ, especially in photo communities, that's a very handy feature to have. Firefox is slowly gaining on Opera.