The former Lyon striker came off the bench with his side struggling against Brighton and netted a 66th-minute winner on Tuesday.
It could be that goal was a major turning point in the fortunes of manager Mikel Arteta, who had come under pressure prior to Christmas due to a wretched series of results.
The Gunners, though, have now won each of their last two, including a thumping 3-0 victory over Chelsea last weekend, and Lacazette’s goal was critical in maintaining the positive vibe.
Similarly, Arteta’s men are expected to pick up three points against the Baggies.
There are expected to be few shifts away from the side that won at the AmEx Stadium. Emile Smith Rowe and Buyako Saka will be preserved in attacking midfield role, though Pierre-Emerick Aubameyang will be shifted to the left in place of Gabriel Martinelli. Lacazette will fill the void in attack.
The defence, meanwhile, will go untouched, with Pablo Mari again replacing the ill Gabriel, who is expected to return to action next week.
Equally, all-action midfielder Thomas Partey continues to nurse a thigh problem but could also be back in time to tackle Newcastle in the FA Cup next Saturday.
West Brom, who recently held both Manchester City and Liverpool to draws away from home, are without Andros Townsend and former Arsenal defender Kieran Gibbs due to injury. Jake Livermore, meanwhile, will serve the second of a three-match ban.
Sam Allardyce’s side have lost their last three at home, conceding 13 in the process. The new boss, who saw his side lose 5-0 to Leeds in his first game at the Hawthorns, will expect a far more robust display this time around.