Arm on the back of your chair?

i always sit next to a male friend of mine in church...almost every week we sit next to each other...recently, however, he started putting his arm around the back of the bench as we sit together. initially, he started with just having his elbow there and kinda leaning on it but now he'll put his arm around me and several people have asked if we're a couple...

am I supposed to be making anything of this? is this normal? do guys do this with their good female friends or do they hope that itll eventually lead to more?