I have an iPhone (iOS 5.1). I added a new telephone number to a new address book entry yesterday and today I find that neither the iCloud Web interface nor my address book on my desktop (OS X 10.7.3) know anything of the new entry.
I was used to automatic syncing via the Internet from MobileMe. Does it not work like that with iCloud?
(Calendar syncing appears to work. Both calendar and address book are switched on on both the iPhone and the iCloud control panel on my desktop.)