LMO approved -> now work permit

Hi,

I am registered as a full time student with my student permit valid until june, 2012 and a student multi-entry visa valid until dec, 2012.

I've been offered a full time job, the company asked for an LMO, and they received the positive response this week (after 4 months since application). I now need to apply for the work permit (and visa). I have to go abroad for a trip planned in February until 11th of march.

My question is: Can I apply for my work permit before leaving the country, or do I have to be in the country for the full time that the application is being reviewed? Will leaving the country affect my application, could they let me not get back into the country?

Anyone know? THANKS!