If Shmoop were snarkier, we might take this opportunity to shout a resounding "duh!" But we'll restrain ourselves.
As readers, we're closest to Elisa. We see the world (almost) through her point of view, and we identify most with her (undeniably mysterious) emotions. Plus, let's remember that chrysanthemums from which the story gets its title are solely her domain. "The Chrysanthemums" is all about Elisa, and Elisa is all about her chrysanthemums.