I had similar issue, this what I did:
sprouted ones: planted them in the pots. they will go in the ground after the last frost.
Un-sprouted ones: I planted them rightaway, in the ground.
( btw, Lilies do better if you plant them in the spring)

I would put the pots outside, maybe on the east side of a building, but not on the south side. As to the un-sprouted ones, if you really don't care to plant them in the ground now, I think I would also pot those. You could probably keep them in a cool place for about a week, but remember that lily bulbs can dry out easily. If your temps threaten to drop below freezing you could move them into the garage.
Chowdhry, I'm curious as to why you feel lilies are best planted in the spring? Everything I've heard or read says fall is the ideal time. I'm not trying to be a smart alec, I would really like to know your reasons.

Although most recommend planting bulbs during the fall, I plant them in the spring when ground is not frozen any more. Perhaps it has something related to bulb matuarity or cold. I order my bulbs in the spring and plant mostly asiatic/hybrids. My personal experience is that they are more vigorous, blooms are larger and they have better survival rate. btw, my zone is Canadian 6b which is USDA 5.

Thanks. When the snow melts tomorrow IÂll move the potted ones outside. I will have to keep an eye on the as-yet unplanted ones. I should learn. But that would be out of character.

I wish more stuff would pop up so IÂd know what spaces were empty. I canÂt remember when the lilies showed last year. Maybe IÂll post on this, specifically, see what others have to say.

Thanks for your response. I haven't experienced a difference, other than the spring planted bulbs tend to bloom a bit later that first year.

For me asiatics seem less affected by planting in the spring. I will still get some bloom. Orientals though seem fussier and will really underperform. I have wondered if it is actually due to the spring planted items being out of the ground too long (assuming they were dug in the fall before selling). When I have transplanted lilies from my own garden, they didnÂt miss a beat.