All fixed! Almost the moment I hit send on my post, I got a note from our hosting peeps saying they'd restarted Apache for me.
Rah and hurray for (all-too-rare) speedy customer service and efficiency! It usually takes me longer trying to remember which email address is associated with our account in order to submit a ticket than it does for them to actually fix what I need them to fix. Although I'd rather if I could simply restart Apache on my own. But they—understandably—have it locked down so only they can manipulate Apache stuffs.)