Adam Fisher’s men began the weekend in third place, but now sit eight points clear at the top after their 10-wicket rout of Upper Wharfedale.
Jake Temple took 4-20 as the Rams were dismissed for just 124, Joe Daggett scoring 44 of those runs.
Liam Storm (66 not out) and Peter Carr (34 not out) then led the new leaders to 125/0 in 26.4 overs.
Arthington slip from first place to second having failed to chase down West Tanfield’s first-innings total of 172 all out.
Opener Harry Lamb hit 73, while Will Shaw added 46, Amaninder Singh bagging a fine haul of 5-33.
But Arthington’s batsmen failed to fire, Kamrosh Khan (34) the only home player to make any real impression as they were bowled out for 147.
Tanfield ace Lamb completed a fine afternoon’s work by snapping up 3-10, while Angus Shaw claimed 3-30.
Goldsborough drop to third having lost a low-scoring affair with a resurgent Masham side, who have now won three on the spin to pull clear of the drop zone.
Jarrod McPhee took 4-13 and Mark Wood 3-8 to help knock the hosts over for just 71.
But that meagre target proved beyond Goldsborough, who were skittled for only 61, Max Eckersley (4-6) and Sam Ambler (3-14) doing most of the damage.
Sam Halliday (130) smashed a superb century as fourth-placed Killinghall put 234/6 on the board away at Birstwith.
Sam Ryan took three scalps then hit a fine 70 for the hosts, though they were all out for 144 in the end, Dan Atkinson scooping 3-19.
Elsewhere, fifth-placed Helperby bowled Pateley Bridge out for 108/7, Joe Corner grabbing 3-15 as Tom Fryer hit a defiant 51.
Corner (36) then helped the visitors to 111/8 despite the efforts of Fryer, who took 5-38.
At the other end of the division, rock-bottom Darley breathed a bit of life into their survival bid when they overcame fellow strugglers Kirk Deighton.
Jim Grange (51) and Joe Furniss (49) led the way for the basement boys, steering them to 205/7.
Ben Cutts (5-28) and Michael Beecroft (3-19) then combined to send Deighton packing for 103.
That win was just Darley’s second of 2023 and leaves them 24 points from safety with three matches left to play.