I'm not sure how we could find out. I would be curious to know this too.
As for other evidence of premeditation, he posted on many (4) of his sock puppet accounts asking for video of the 1 Lunatic 1 Icepick video on May 15th. That is 9 or 10 days from when the murder even occured. So clearly he was planning to make the video and he thought of the name at least 9 days prior to the actually murder.
May 15th:
Dailymotion user "anonymousgirl33" posted two videos on May 15th before the murder occurred asking about 1 Lunatic 1 Ice Pick:
http://www.dailymotion.com/anonymousgirl33#video=xquz78
Both of the videos posted on that account only show a picture of a man in a hoodie with an icepick in his hand and a movie poster of Casablanca behind the man on the wall. The poster was in the killvid, along with an icepick and a hoodie (not sure if it was purple.)
YouTube account "alexisvaloranreich" where two videos were posted on May 15th:
http://www.youtube.com/user/alexisvaloranreich
These are the same two videos he posted on dailymotion.
This is the description on the first video he posted:
This is the second video's description:
Psychforum Post "anonymousgirl4" where he goes into detail about the 1 Lunatic 1 Ice Pick video, 9 or 10 days before the actual victim was murdered:
http://www.psychforums.com/antisocial-personality/topic89464.html
Answerbag.com Question where the user "Aiden_V" asks about 1 Lunatic 1 Ice Pick video, before the video was out.
http://www.answerbag.com/q_view/2727749
Neoseeker post where the user "briankinney556" asks about the 1 Lunatic 1 Ice Pick video, again before the video was created:
http://www.neoseeker.com/forums/18/t1734430-1-lunatic-1-ice-pick-video/
EDIT: WTF!!!
There is a forum named "Oh Look, a Forum!".. I'm not sure what it's about, but I saw a Gore section.. anyway, the account "babymaggie11" posted on May 15th at 4:23pm asking for the 1 Lunatic 1 Ice Pick Video..
http://www.ohlookaforum.com/viewtopic.php?f=2&t=17600
The person responds on MAY 15TH, AT 7:59 PM with this comment:
It does not say the post was edited. I'm hoping they just have the hide edit feature off or something, because if this person new Luka was making a snuff film before it was shot, then they need to be question by LE..
EDIT 2: The person that responded to Luka on the forum "Oh Look a Forum" more than likely edited their post to put "p.s. Hi Luka!". They refer to that post in a different thread about the whole Luka Magnotta story.. so no need to be alarmed that the person somehow knew Luka pre-murder