I have several calendars synced using MobileMe and after upgrading to Lion it is often the case that a day's worth of newly added events all disappear. This generally happens when I am in another application. Often, if I re-add the same event later, the old events re-appear, giving me duplicates. However, if I never re-add the events, the old ones never come back.
The events that are missing from my Mac still appear on my iPhone, but attempting to re-sync does not bring the events back to my Mac.
I have tried clearing my iCal cache and preferences while the events are missing, but this does not seem to bring them back.
So, why are my events disappearing in iCal and how can I fix it?