The Snuggie's back on.
Thinking I'd resolved the thermostat issue when I left for work today, I was excited to return home to a toasty apartment this evening. Alas, my efforts were unsuccessful, and I met an indoor temp of 14C (57F). I am focused on finding a solution and have been isolating variables to determine which button and dial combination yields the most heat. Given that the thermostat now registers 16C, I may be on the right track.
In the meantime, it's all about the Snuggie (thanks again, Grandma!).