iCal sends from iPhone4 BUT.

First check that all your settings are correct, that calendar syncing is checked on all devices (system preferences > iCloud on a mac and settings > iCloud on a iPhone, iPad or iPod).

Make sure the calendars you are using are in your 'iCloud' account and not an 'On My Mac', 'On My Phone' or other non iCloud account (you can do this by clicking/tapping the calendar button in the top left corner of the application ), non iCloud calendars will not sync.

If you are sure that everything is set up correctly and your calendars are in the iCloud account, you might try unchecking calendar syncing in the iCloud settings, restarting your device and then re-enabling calendar syncing settings.

On the Mac, click the calendars button in the top left corner of the iCal window, this will reveal a list of your calendars and the accounts they are in. You can do the same in the main calendar window of calendar on your iPad.

Yes, there should be an iCloud section on the calendars. If there isn't check that you have calenders turned on in settings> iCloud.

When you create appointments, do you get the option to choose a calendar, and if so is the iCloud account listed as available.

Are you able to make an appointment in that calendar, and when you do so, does that calendar show up under your list of calendars.

You said, or at least I understood you to have said, that when you create an appointment you are offered a list of calendars that includes an iCloud calendar, is this correct or not.

Nothing actually pops up in this respect, it's one of the options when you set your appointment details.