I have a 2011 MBA (13", 10.7.2, 256 GB). Very often, when I open the lid (and the MacBook is sleeping) the system freezes for 2-3 seconds, then the display blinks; after that, the system waits 1-2 seconds to respond. Normally, it would take only 1-2 seconds (I think) to respond after lid is opened. When the lid is opened, the display always turns on instantly.
So, is this normal? If not, what can I do to solve it?
Edit: I don't have an external monitor or any USB devices connected.