The on-loan Bristol City midfielder made it two goals in two games with a long-range third-minute lob that stunned Walsall.
It looked set to earn Cheltenham only their second away win of the season and keep their slim survival hopes alive.
But they were denied a victory in the 67th minute after Walsall were rewarded for an improved second-half display when Dwayne Mattis saw his shot turned into his own net by the unfortunate Michael Townsend.
Cheltenham are now unbeaten in five games but that is little comfort as they head towards League Two.
Walsall were caught cold by the vision of Artus as his quick thinking paid off in spectacular style.
Artus was some 40 yards from goal when he collected a short free-kick from central defender Townsend. He took a quick look up and saw that goalkeeper Rene Gilmartin, who was in the side because Clayton Ince was on international duty with Trinidad and Tobago, was slightly off his line.
Artus let fly with a dipping drive that dropped over Gilmartin and just under the bar. It was a shock that Walsall struggled to come to terms with despite the best efforts of Troy Deeney.
Deeney, who had scored nine goals in his previous 15 appearances, twice tested Scott Brown with close-range headers while Manny Smith saw an effort slide wide.
Walsall continued to crank up the pressure at the start of the second half with Alex Nicholls wasting two clear chances when he was denied by Brown before Sofiene Zaaboub hit the bar with a curling free-kick.
Their persistence finally paid off when Chris Palmer whipped in a right- wing cross that was met by Mattis before Townsend got the final touch to take the ball across his own line.
Walsall could then have gone on to win the game only for Brown to come to the rescue of Cheltenham with a stunning save in the 73rd minute to keep out a goalbound header from Nicholls.