Henry Arundell will be ineligible for England until June 2026 after his contract extension with Racing 92 was confirmed.

Arundell has made a flying start to life in Paris and has signed with Stuart Lancaster’s club for another two seasons, ruling him out of Steve Borthwick’s plans. The 21-year-old’s decision to commit to Racing is a hammer blow for the Rugby Football Union, who hoped to make him the poster boy of the “hybrid” contracts that will be introduced next season.

Related: The Breakdown | Arundell’s French adventure puts pressure on Borthwick and RFU

Arundell had the chance to join Bath, with the RFU topping up his salary as one of 25 players over whom Borthwick will be able to exercise greater control, but has chosen to continue learning his craft under Lancaster instead.

Arundell joined Racing after the World Cup following the demise of London Irish last summer. Initially he had expected to be available for the coming Six Nations by taking advantage of the RFU’s exceptional circumstances loophole but, encouraged to make a decision on his long-term future before the championship, Borthwick will now be unable to pick one of English rugby’s most exciting talents. Borthwick even paid Arundell, who scored five tries in one match against Chile at the World Cup, a visit in Paris last month, but failed to convince him to return to England.

“We are delighted to see Henry extend his commitment to Racing 92,” the club’s president, Laurent Travers, said. “He has just joined a few weeks ago but has already demonstrated all the qualities of a great competitor and great maturity. He fits perfectly with the club’s short_ and medium term objectives and we are convinced he will be one of the driving forces to achieve them.”

The RFU’s hybrid contracts have been designed to allow Borthwick to manage his players better all year round but have come to be a means to keep England stars in the Premiership amid a growing number seeking moves abroad.

Arundell is joined in the Top 14 this season by fellow England World Cup squad members Joe Marchant, David Ribbans and Jack Willis as well as Jack Nowell, Sam and Joe Simmonds and Jack Singleton. Lewis Ludlam is expected to join Toulon next season while Maro Itoje and Kyle Sinckler are said to be considering their options.