Evidently this is a not-wildly-uncommon error that WordPress gets. Something happens to disturb the userid/password/host database connection, and suddenly (the downside to a fully dynamic system) there is no blog.

That this came up first thing in the morning for me was a bit embarrassing. Fortunately, I was exchanging messages (on a completely different matter) with Stacy, and she was able to poke into it. I tried all the standard stuff, including creating a new database id and password and updating the wp-config.php file … but it had no effect. Stacy did it, though, and it worked perfectly, which is why I’m no longer in tech support.

So back up and ready to rock, huzzah.