According to Catholicism, who are “the elect”?
In a nutshell, this term for Catholics refers to the Church Militant and the Church Triumphant.
Here follows what the Catholic Encyclopedia has to say on the subject of the Elect:
Denotes in general one chosen or taken by preference from among two or more; as a theological term it is equivalent ...
If you want a good overview of Catholic doctrine on predestination (and then you will be able to understand who are the elect), the best is the two-part lecture: Are you saved? part1, part2.
The second part is more fully devoted to predestination but the first part is a requisite. The lecturer comments on the Calvinistic theory (their mistake is the ...
Catholics also believe, according to Parente et al.'s Dictionary of Dogmatic Theology p. 84, that "the elect" are
Those predestined by God to eternal life [heaven].
The difference between Calvinists and Catholics regarding predestination is that Calvinists believe
that some are freely predestined, and the rest are freely and positively damned. ...