Gee, I am in a colder zone than (almost) any of you, and nearly all my lilies are up now. Though as a species, L. superbum is commonly found for sale, I haven't grown it, as I much prefer L. michiganense, which is essentially a smaller form of superbum. L. superbum would prefer a moister area (as would L. canadense), but it is a very forgiving species, and will take regular conditions, too, and be happy. I should say, I haven't grown L. superbum until now, as last winter I received some excellent seed from a stand of mixed coloring, from Joe Nemmer.
Also excited that 6 out of 7 seed germinated of a dwarf form of L. pardalinum. They produced their tiny bulbs at 50 degrees F, but refused to send up a leaf until I exposed them to light.
In actuality, any lily can skip a year or even two of above ground growth. Some are just more prone to it than others. I had planted very very late in the fall my first aurelian hybrid bulbs that I had hybridized. It had even snowed once already. The following season, only about a third of them emerged. I figure the others had probably frozen. But now, here they all are this spring,
seemingly happy as can be.