" In its best-established sense, fortuitous means "happening by accident or chance." Thus, a fortuitous meeting may have either fortunate or unfortunate consequences. For decades, however, the word has often been used in reference to happy accidents, as in The company's profits were enhanced as the result of a fortuitous drop in the cost of paper. This use may have arisen because fortuitous resembles both fortunate and felicitous."
I've used this word a lot in my life. I think perhaps I've misused it as well. Apparently its use has developed over time to not only mean "happening by accident or chance" to "happy accidents". I generally use it in the latter sense myself by exclaiming gratefully "How fortuitous!" when someone happens by at a great time or when circumstances and chance combine to create great opportunities.
I'm generally open to seeing - and naming - fortuitous events, such as meetings. Haven't you experienced running into an old friend and spontaneously going to get a cup of coffee? Isn't it wonderful to have a change of pace just land in your lap like that? What about when the "six degrees of separation" thing happens - and the person you call or meet knows so and so whom you know?
I've heard many people allude to the former meaning of fortuitous, when speaking of my disability. It really floors them when I go on to say that my life has been enhanced as the result of a fortuitous accident and by the experience of living with a disability.
The word fortuitous has a funky history. The consequences can go either way. It reminds me that being grateful for the happy consequences sure beats dwelling on the unhappy ones, no matter whether my usage of the word is completely accurate - or not.
But all in all I'm kind of glad that the word fortuitous has evolved toward a more fortunate meaning. Because it's a lot of fun to say it.