CRA accepts, based on Rezek, that elections required to be filed with a return are considered timely even if the return itself is late

CRA accepts the Rezek decision for the proposition that where there is a requirement to file an election with a taxpayer's return, the election's filing will be considered to be timely if the election is filed with an overdue return.

However, the converse also holds - an election filed after the return's filing will be considered late even if it is filed before the return's due date.  This is problematic for electronic return filing, where electronic filing of elections "in the return" is not accommodated.  CRA is considering administrative concessions, as discussed in 9 November 2012 CTF Atlantic Roundtable Q. 8, 2012-0465981C6.

Scott Armstrong.  Summary of 18 September 2013 T.I. 2013-0487871I7 ("Filing Due Date for Elections") under s. 220(3.5).