The 18-year-old joined from Romanian side Viitorul Domnesti last year and signed his first professional contract with the Gunners a year ago.
Cirjan started life at Arsenal with the Under-18s but in July he was fast-tracked to the Under-23s due to his impressive performances.
Cirjan, who plays as an attacking midfielder and is also capable of play on either flank, is yet to make his debut for Arsenal’s first team.
But the midfielder is now one step closer to making his senior breakthrough after Arteta decided make him a full-time regular in Arsenal’s first team training sessions.
‘From today, he will train daily only for seniors, he is confidently waiting for his debut in the Premier League,’ said the midfielder’s representative Catalin Sarmasan.
Cirjan was joined in Monday’s first-team training session by four other Arsenal academy prospects – Miguel Azeez, Folarin Balogun, Ben Cottrell and Nikolaj Moller.
Azeez was handed his first-team debut by Arteta earlier this month as he came on as a late substitute in the 4-2 win over Dundalk in the Europa League.
Meanwhile, Balogun was also give his first-team debut in the Europa League this season and the 19-year-old forward has scored two goals in four appearances.
Cottrell also made his first-team debut in the win over Dundalk, while Moller is yet to make a senior appearance for the Gunners.
‘You have two types of people – fighters and victims,’ said the Spaniard.
‘You need fighters and you don’t want any victims. Victims bring excuses, victims bring negativity and they start to blame anything that is happening around them or is not going their way.
‘You need people who fight, people who contribute and people who are ready to give everything to the club in this moment.’