The Lilium genus is very diverse, and indeed there are species that can (also) germinate at 2-4C. Often, these are ones said to germinate at 10-14C, like L. pyrenaicum, pomponium, possibly the Balkan species. Perhaps it is the variation in the individual species themselves, perhaps it involves certain other developments in the embryos. With L. pomponium, for instance, I have found different batches of seed (from different sources) germinate best at, say, 12C, and some best at 2-4C. With some seeds, and I do not doubt that this might include some Lilium, germination will take place at most any temperature, say 2-25C. Prior exposure to a warm cycle, or even a week or two in moist warm conditions, can also affect cool or cold temperature germination.