I think you mean Poor man's black velvet, not poor black man's velvet, which has a whole different connotation!
Black velvet is 1/2 guinness, 1/2 champagne, and from my days as a barman, a poor man's black velvet was 1/2 cider 1/2 guinness.
Can't say I was ever tempted to try it...
A proper Black Velvet was Guiness and Champagne, and a poor man's version was meant to replicate it obviously - so that would not include cider. A poor man's Black Velvet was Stout and Babycham! I drank it for years in my youth and can testify that it was lovely.