Mr. Speaker, this is indeed a matter of decorum.
This is what it says on page 613 of House of Commons Procedure and Practice:
13. Rules of Order and Decorum
Rules Regarding the Contents of Speeches
References to Members
During debate, Members do not refer to one another by their names but rather by title, position or constituency name in order to guard against the tendency to personalize debate.
However, today, in the statements before question period, a member with 688 days of experience in the House, the hon. member for Manicouagan, deliberately and viciously named a member of Parliament.
Mr. Speaker, I urge you to read his statement in the blues, and you will see that that is what happened. I hope that you will make the decision you feel is best.