[forgotten man]

I would say “If I were on fire...” because I am not on fire and have no intention of setting myself of fire. If I am on fire please throw water on me. I need to look that one up in my grammar book.

[William Tell]

Your usage appears to be correct.

Here’s a link supplied by a link above.
http://web.cn.edu/kwheeler/grammar_moods.html

It would appear that my high school teacher oversimplified the topic.

[William Tell]

Here’s the link I meant to post:

http://web.cn.edu/kwheeler/grammar_subjunctive.html

It goes into some depth regarding the subjunctive mood.