The 35-year-old hitman was handed a new one-year contract by Bantams boss Stuart McCall in the summer despite seeing his first season at Valley Parade ravaged by injury.
Thorne sat out the start of the last campaign with a hip injury, but goals midway through each half secured the points for the home side in front of a bumper West Yorkshire crowd.
McCall has brought in nine new players since the end of the last campaign in a bid to mastermind promotion from League Two at the second time of asking.
Four of those signings started the game, but it was veteran Thorne who caught the eye with a two-goal blast.
Both sides had traded shots straight at the opposition keeper from Kyle Nix and Jamie Forrester, before Thorne pounced for the first time in the 21st minute.
Last season's 15-goal marksman rose on the edge of the six-yard box to head home a right-wing cross from debutant Paul Arnison to break the deadlock.
The Bantams maintained the upper hand as the half continued and lively winger Omar Daley drew two fine saves out of Kevin Pilkington in the space of as many minutes.
The Jamaica international saw a follow-up shot from a 38th minute corner parried by Pilkington, before the former Manchester United keeper tipped a drive from the edge of the box around his upright.
Daley also drilled a left-foot shot straight at the keeper as the first half drew to a close.
After the interval, it was the home side who continued to hold the upper hand and it was little surprise when the impressive Thorne doubled his tally and his side's advantage just after the hour-mark.
The former Stoke City and Cardiff striker dispatched an overhead kick from close range after 61 minutes.
However, County reduced the arrears with 20 minutes remaining when Richard Butcher converted Myles Weston's cut-back from the left touchline.
City sent on Michael Boulding with ten minutes remaining, but the summer signing from Mansfield Town struggled to make an impact as the visitors stepped up the pressure in the closing stages.
But despite being under the cosh for a ten-minute spell towards the end, the Bantams held on to secure the points and a winning start to the new campaign.