Interestingly...

...I lost that 1.5 lbs within 24 hours. On top of that, according to my scales, by yesterday (Monday) morning I'd lost 6 lbs! The fact that the blip last week consisted mainly of carbohydrates, which hold onto water, would explain the weight gain, and the subsequent weight loss when I was back into ketosis again. So I'm very encouraged that my weight loss this week will be generous. :-)