With that late hard freeze, I've noticed many of the trees and shrubs are later than normal. Depending upon your micro-climate and how cold it got at you place. I wouldlet it be for a couple weeks then slowly prune back little by little until you hit live wood. As lace-leafs are all grafted, any live wood above the graft knot should recover.

You can pinch the bark on a twig with your thumbnail and see if it's green underneath. If so, still alive. If not, keep moving down the branch until you find green. It's early still to declare something dead. I have one that's just starting to leaf out and another that's fully leafed out.

Mine in one area is fully leafed out, others in more shade are still in leaf bud. You should see some growth in the leaf buds by now, and dead branches will be gray and brittle. If the branches aren't brittle, I'd let the tree be for now; they are very tough trees and will make growth from the least bit of live wood.

Fungal/bacterial diebacks seem to be common on these here now, on another site it has been suggested that a few growers are sending out pre-infected stock. Usually with these conditions portions of the plant blight away over a period of years, but not always--I think it's not rare for most or all of the top of a young specimen to be lost all in one go. Verticillium wilt is a common diagnosis, but is not the extent of it.

If you don't have excellent drainage I suppose that might cause sudden failure of an entire specimen, these are a bit touchy and we did have that rainy March.

I agree that Verticillium is a likely cause of this. Some years back, a neighbor and I lost 3 maples the same year. I don't attempt them here anymore. I had the exact same experience that you are now having. Sorry.

I bought a healthy Crimson Queen Lace-leaf Japanese Maple 4 weeks ago. After about 2 weeks I noticed that the leaves started wilting/drying and curling. When I touched the leaves they just fall down. This tree gets a lot of direct strong sun for 4-5 hrs per day. The soil in my area is very clayish. I dug a little soil around the tree to see if tree is drowning or suffocating and I saw that there was pool of water around it. Looks like the soil in my area is not draining but retains all water. Would this property of soil drown the tree? Do I need to move it somewhere else. Is it enough if I remove the tree add a little soil under it to increase the height and replant it in same place ? I also tried to break some small branches and it looks like some are brittle and they easily snap. The bark looks green. Please advise on options. I don't want this beautiful tree to die. Is there a test to tell if it is alive.