Chelsea striker Romelu Lukaku was delighted after playing a key role in his side's 2-0 win over Arsenal, describing his performance during his debut as "dominant".The Belgian, who joined from Inter in a £ 97.5m deal earlier in August, wasted some time getting started on Sunday and scored his first goal for the club within 15 minutes of concluding a post from Reece James, and he continued to bully the Arsenal midfielders throughout the game.Immediate impact. ? pic.twitter.com/lCMmZUnJI5- Chelsea FC (@ChelseaFC) August 22,…