Brian, there could very well be a positive outcome even after a freeze. Lots of times, if the freeze hasn't penetrated deep enough into the 'core' of the main stem, a good healthy bulb will continue to grow right on up and thru the frost bit section and recover fully. The frost bitten leaves would then simply dry up in time. The other positive scenario even if it has sustantial damage and you get at least some growth; your bulb is still healthy with lots of energy reserve, it will want to expend that energy in survival mode some way--usually by generating more offsets. So, don't panic or do anything drastic just yet--wait a couple two or three weeks and see what happens. Like Polly says, they generally always come back and at some point you might want to top it before blooming.
I've never had a heathly bulb totally 'shut down' from a hard freeze. Like Leftwood, I mulch late and try to hold my stuff back as long as possible. But like you say Brian, this last winter was a real challenge and this way above normal spring just made it even more worrisome. By some lucky sequence of weather events we did not frost here during the last cold spell; my lowest was 36.4 F. but it will freeze here yet, I'm pretty sure.
