After a couple of telephone conversations with Apple Support and three visits to Apple Stores the conclusion is that, since I discovered the loss only after a couple of automatic syncs and iCloud backup is only as good as the last one, about half of my contact list (approx. 200 contacts) was lost. Of those remaining many had only parts deleted, e.g. telephone numbers or email addresses. iPad can be set up (on the PC) to back up Contacts to MS Outlook instead of iCloud (not both), which is one way to secure Contact list isn't lost completely. I don't use the MS Outlook on my PC, and only because of inadvertent syncs between my now useless Palm Zire device and MS Outlook about two years ago, I was able to recover the Contact list from Outlook. To prevent future Contacts loss I have now installed the My Contacts Backup Pro app, which backs up Contacts in an e-mail. I suspect the original Contacts loss is connected to a Skype program update.