iPhone & iPad iOS 8.3 Contacts & Calendars will not update when syncing with iTunes on iMac

I have an iPhone 5 and iPad 3rd generation. Both are running iOS 8.3. I always update the iOS a few days after release.

I also have an iMac which is up-to-date (OS X 10.10.3). When syncing with iTunes (12.1.2.27) my Mac I no longer see the requests during the sync asking me which of the compared or new entries to add/modify in Contacts or in Calendars. Since I often make changes on the iPhone, I need to have those changes added to the iMac and iPad contacts, but at the moment I have to do so manually.

I've looked at the settings in iTunes and on the devices, but so far don't see anything I need to change. I have checked the sync all Contacts and sync all Calendars, but this seems to have no effect.

I don't use iCloud and I'm wondering if this has some bearing on the problem. Are we required to use ICloud in order to update and sync Contacts and Calendars?

(My apologies if this has been addressed elsewhere. I did a few searches, but didn't find anything recent on this topic.)

Thanks in advance for any assistance.