After about 5 seconds after starting the car this evening from cold, it stopped very abruptly. I thought 'ignition' and checked for a loose wire, but to no avail. Then looked at the fuses and, sure enough, one of the 'stubby' ones had failed (or succeeded, depending on how one looks at it). I replaced it, started up again and, again after about 5 seconds, the car stalled. Fuse blown again. I then noticed that the battery ground (-) cable was touching the ballast resistor. Last evening I replaced the battery and did not route the ground cable properly. After fixing this, replaced the fuse one more time and this did the trick.
I was pleased that I was able to pinpoint the problem so quickly, but was also embarrassed I had caused it ...