Here's a short story, only four pages, and the original title gives some hint as to the plot in a way that the current title doesn't: “An Easter Day Conversion” clearly tells us this is a special event; "A Morning Walk" sounds like one of many. Maybe the new title lets the plot creep up on the reader?
In any case, it doesn't creep up slowly. From the first we meet Archibald, all we hear is that he seems older than he is; he's more practical and scientific than poetical and sentimental--"For he leaned decidedly toward practical science; of sentiment he knew little..."; and that he's pretty inattentive to women.
Except that's the first page; already by the second we're hearing that today feels different for him--now he's noticing beauty. So already, by page two, we have something of a conversion. Where do we go from here? Well, Chopin keeps us between these two states--between the practical man of page one and the sentimental man of page two.
Whenever Chopin wants to stress the sentimental--as she does when Archibald meets young (20 years old) Lucy--she lets her sentences become compound and complex, as if all these ideas are suddenly flooding the usually staid Archibald:
He looked down into the girl’s face, and her soft, curved lips made him think of peaches that he had bitten; of grapes that he had tasted; of a cup’s rim from which he had sometimes sipped wine.Not only is Archibald thinking in metaphor, but in multiple metaphors. So here we see the eventual endpoint of this Easter conversion: Archibald will become a lover of beauty, women, and life--and also probably Christ, though that seems to be downplayed.
But since Chopin never gives us a reason for the conversion; since she keeps us on tenterhooks between Archibald's two states; by the end of the story, I feel a little uncertain as to why we ended up where we did.