More good luck ... my brother Won was in town. He is an electrical engineer. Not only did he help me replace the elements, he taught me how to use a multimeter. Now I can regularly measure the resistance in my elements so hopefully I will see it coming the next time one burns out.
But here's the "hard lesson" part of the incident. 5 out of 6 of the elements were not ready to burn out. One of the elements was broken, with a little pile of burnt crud surrounding the break. I had probably placed a pot too close to the element, and allowed a bit of glaze to chip off into the element holder. I used to have a "one inch rule" about placing pots close to an element. Lately I had broken that rule a lot, thinking that getting one more pot onto a shelf was justification. It's not smart to replace one element by itself, they should all be of the same age and similar resistance. So having to replace 5 working elements really offends my inner cheapskate.