There have been a number of Lovecraft games already ( Shadow of the Comet and a sequel whose name I forget involving submarines, nazis and demons buried under ice ) but more importantly, there is a new Call of Cthulhu game in the works. This suggests to me that the copyright is still very much in effect.
A quick google confirms that he died in March, 1937.
A quick google confirms that he died in March, 1937.