One of the major disputes in Hume scholarship in the past twenty years or so has been the "New Hume" position. On the older reading of Hume, often called the 'Postivist' or the 'orthodox' view Hume denies that there are real causal connections among external objects. The New Hume interpretation is a popular counter-interpretation, which holds that Hume does not deny that there are real causal connections among external objects. Rather, he is a "Skeptical Realist" about them: real causal connections exist, but we 'cannot conceive them'. Part of the inspiration for this is that Hume does talk a lot about the 'hidden powers' of things, and one way to take these statements is to interpret them as affirmations that there are hidden powers.
I tend Old Hume myself, and in any case I think it matters less than most people seem to think; but one argument that can't be used against the New Hume interpretation is that, since Hume says we can't conceive of what real causal connections are, it makes no sense for him to believe there are real causal connections. What this overlooks is that Hume does on occasion allow that we can suppose things to exist that we can't conceive -- for example, we can't conceive of an exact standard of equality, but we can suppose one to exist.
Incidentally, you can get back issues of Hume Studies online; the newer issues are restricted to members of the International Hume Society, but the older ones are public. (If you do work in Hume or involving Hume and are not a member of the Hume Society, you need to be; it's a great group.)
