That is correct. There will usually be a period of about a month, after they bloom and before they start to set next year's buds, when you can prune. I like to do the main portion of the pruning just as soon as the blossoms fade; the plant usually starts to make the new leaves within a week, which is just soon enough to give me time to do a bit more pruning if I think the appearance can be improved. Don't forget to remove one of any crossed or rubbing branches before doing the shape-pruning.

I always prune mine while they're blooming. Then I put the cut branches in water and enjoy them in the house or on the porch.