ORCHARD PARK, N.Y. — The Broncos were told all last week it was a trap game. They were told that two impressive victories at home to open the season meant little when they traveled to Buffalo. Those who said so were proven right. The same Broncos (2-1) that contained Chargers quarterback Philip Rivers and shut down Cowboys running back Ezekiel Elliott lost to Buffalo, 26-16, here Sunday. Quarterback Trevor Siemian completed 24-of-40 passes for 259 yards, but threw two costly interceptions in the second half leading to Buffalo taking a lead it would not relinquish. The Broncos’ defense that came out swinging with a pair of first-quarter sacks struggled to clean up the offensive miscues and penalties that plagued Denver. Denver got on the board first as Siemian engineered a 12-play, 53-drive that was aided by a pair of defensive pass interference calls and ended with a 38-yard field goal by Brandon McManus.