I had the briefest of freezes this year here in norcal and darned if most leaves didn't brown. Happens. I just wait until they are so dry you can almost knock them off with your hand. Won't hurt either if you prune them off. Might inspire the tree to get going.

Thanks for the reply. Here is the relevant information that I received today from a generalist plant expert : "...advantage in removing the dead leaves no later than the point in time when the plant starts pushing new growth; reason: the leaves being removed will increase the amount of light striking the middle of the tree, which increases the probability of back-budding. The increased air movement afforded by removal of the dead leaves increases the rate of respiration, which in turn increases the speed of the nutrient stream.... increased growth rate results. The dead leaves in no way represent a direct drain on the plant's energy reserves, but as noted can have a negative influence nonetheless.