Both my wife and I got immigration visa to Canada. My wife plan to land Canada and then come to US next month. However, the lawyer told her not to apply for H4 (I am holding H1) at US consulate at Beijing at this moment since there is Canadian immigration visa on passport and the US consulate may deny the visa application. We are wondering whether it is possible to apply for H4 at US consulate at Canada in this case (after landing but before getting Maple card)? Also, how long will it take to get Maple card?