Thanks, all, for the input. Looks like you are all correct. I gently pushed on the lid last night, and, sure enough, built up gas was forced to escape. Then, this morning, bubbles in the air lock! So I feel better. However, I have certainly learned a few things: 1) don't depend on bubbles in the air lock for certainty, 2) as a habit, always pitch the yeast at cooler temps, and 3) inquire at the supply store about starters... Thanks again for the quick replies.