If I knew iCloud was as useless as this I wouldn't have upgraded the account when Lion told me.
When you upgrade it asks you if your iOS devices are all at least a certain version and also the same with your Mac's. It is a pain (I use the odd 10.6 Mac) but they do warn everyone when you upgrade.
My other half did not upgrade when she saw the warning as she was using an older iPhone (with an out of date OS) so she waited until she got a new phone to upgrade.
Edwin