Final answer:
The specific subject of the lauded essay that Lena wrote is unclear from the provided information, but it could relate to the English or literary analysis sphere, possibly touching on themes such as personal growth, literacy narratives, or literature appreciation.
Step-by-step explanation:
The essay written by Lena is not explicitly detailed in the provided excerpts, which makes it challenging to determine its specific subject. However, given the context clues, it seems that Lena may have received praise for an essay related to topics like literacy narrative, personal experiences, or literature analysis. This is deduced from references to literacy narrative genre, Sandra Cisneros's journey as a writer, analyzing Shakespeare in the curriculum, and the mention of an argumentative research essay by a student named Lily Tran that includes well-supported arguments and evidence. It can be suggested that Lena's praised essay falls within the realm of English studies or literary analysis, focusing potentially on themes of love, personal journey, or educational experience.