Arnold was a driving force in creating what eventually became The Arches, eventually taking on the role of Artistic Director. The space had been renovated for an exhibit called Glasgow's Glasgow during the city's term as European City of Culture in 1990, but Arnold pushed for it to be used as a theatre space after the exhibit was over.

Rather than becoming strictly an art and theatre space, the Arches evolved in the 1990s to take advantage of the healthy Glasgow nightlife, with a bar, club and restaurant whose profits fund the variety of artistic events the not-for-profit hosts, be it films, experimental theatre or interactive experiences such as the recent Alien Wars. Patroned by Scottish dramatist and poet Liz Lochhead, alongside larger-than-life London DJ Carl Cox, it was unique in Glasgow for its diversity and known for its passion in discovering emerging artists.

In 2015 Glasgow City Council made the controversial decision not to renew the Arches license. Without those funds, the institution was unable to function and went bankrupt shortly thereafter.