Desperately seeking a deus ex machina

Microsoft Word keeps autocorrecting deus ex machina until I'm tired of fighting it (and also tired of wondering when some deus ex machina will materialize in a cloud of smoke and zap Autocorrect into the stone age) so I'll take a break to seek a grammar guru who will emerge from the internet machine to help me with a sticky problem.

It's simple: my students think although is the same as however.

It isn't. However, this is what I see in student papers all the time:

Although, the deus ex machina failed to materialize.

Just like that: although with a comma attached to a sentence  or a fragment. The sentence would be just fine if they replaced although with however or nevertheless or therefore, but they don't. Maybe they're not familiar with however. Or maybe they think although is essentially the same thing.

It isn't, but so far I haven't found a way to explain the difference without relying on terms like concessive adjunct. What are the odds that someone unfamiliar with however would understand concessive adjunct? Pretty close to nil would be my guess.

Here's where I'd like to adjust Autocorrect so that it administers an electric shock every time a student puts an unnecessary comma after although, but that's just the kind of deus ex machina that never shows up.