I have an extremely rare copy of the 1888 edition of A. B Frost's STUFF AND NONSENSE cartoon book, and it contains the gag that was later developed into L'Arrouseur Arrosee by the Lumieres. This image does not appear in the reprint of the 1882 edition that was published by Fantagraphic Books a few years ago.
The image is attached.
As you can see the gag is is six years older than the film. Since Frost's book was a best seller, it is a good bet that the cartoon inspired the film
In fact, many silent comedies owe something to cartoons, including most early Keystones, quite a few Buster Keaton films, and (amazingly) one entire Roscoe Arbuckle comedy that was a remake of an animated film made six years earlier.
I'm looking forward to discussing this with some of you.
cheers!