I just brewed caribou slobber as well and had a similar concern when the fermentation lag was longer than i expected. Having prepped my Wyeast Northwest Ale 12 hours in advance, making sure the pack inflated, I pitched at 62 degrees when the room temp and the yeast were at 68. There was no sign of fermentation 24 hours later, so I shook the fermenter and checked the temperature again, which had risen to 65, within the optimal range. Now more than 36 hours later, fermentation has started and the temperature has moved up to 68 degrees. It would appear that getting the temperature up was crucial.