Darcis will be going for his 21st win in Davis Cup singles when play gets underway on indoor hard courts at the Spiroudome de Charleroi. But Lorenzi beat him in their only previous meeting, on a similar surface two years ago in Metz.
In Friday's second singles, David Goffin will be up against veteran Andreas Seppi, having beaten Seppi twice before.
The 14th-ranked Goffin has won 11 of his last 12 Davis Cup singles, with his only loss against Andy Murray in the 2015 final.
On Saturday, Ruben Bemelmans and Joris De Loore will face Simone Bolelli and Alessandro Giannessi in doubles. Goffin will take on Lorenzi and Darcis will play Seppi in Sunday's reverse singles.