Ferd II, you genius! It worked like a charm. I changed the region from the default Custom to Canada and iCal again works as it should.
But the bonus that came with your solutuion is even better.
Lion inexplicably changed every single file-modification date on my computer – including those on files I'd backed up on a hard drive.on backup drives – to January 5 2011. I spent days trying to figure out what was wrong. (An answer is still pending from Apple techs who were also unable to explain what happened.)
I was despairing of not being able to retrieve the orginal dates. Naturally, when I saw the dreaded January 5 2011 as the example in the system pref for Language and Text, I figured it was another instance of conversion.
But when I set the region to Canada, every one of the corrupted file dates, all those January 5 2011s, reverted to their proper modification dates! Amazing. The only one that didn't is the example/default in the Language and Text pref box.
I will let Apple's techies know that Ferd II solved the problem.
Thank you so much for your help and for sticking with the problem. I can now sync my iPhone without fear of infecting it.