Hi Sandy:
Spring is the recommended time to prune, and some blooms will be sacrificed. I usually clean up the Rhodys every spring, and if I do this yearly, the pruning is never very severe, and most blooms are saved.
I have had those years tho, when my Rhody's were neglected and turned into the Oversized Jolly Green Giant in the yard. Now my spring pruning will remove every bloom, so I elect to let the plant bloom and prune after.
Would it be possible for you to take a picture of the Rhody to see the height and shape of your plant. Pruning a 5 foot Rhody is not at all that similar to pruning a 10 or 12 foot Rhody. I spent my first few years of learning to prune these things, where I literally would prune the plant, by two feet all over, only to realize the plant still looked like Lurch, and had to start all over again.
