IIRC it was in a friends-locked post (which would be why I didn't link to the entry when I dropped it into my quotes-queue). If you haven't found it yet, I'll help you look.
One trick you can use that I can't, is to go to the download-your-journal page (http://www.livejournal.com/export.bml) and pull the months it was likely to have been in to your local disk drive, then use 'grep' or some similar tool to search for the phrase. Unfortunately there's no way to download all the comments to your journal at once, nor to grab all the comments you've left in other people's journals, so that'll only help if it was something you said in an entry, not in a comment. I don't remember off the top of my head whether it was in an entry or a comment.
(no subject)
When did I say that? *rummages through his LJ*
(no subject)
One trick you can use that I can't, is to go to the download-your-journal page (http://www.livejournal.com/export.bml) and pull the months it was likely to have been in to your local disk drive, then use 'grep' or some similar tool to search for the phrase. Unfortunately there's no way to download all the comments to your journal at once, nor to grab all the comments you've left in other people's journals, so that'll only help if it was something you said in an entry, not in a comment. I don't remember off the top of my head whether it was in an entry or a comment.