Yet he was recently called up to the Ireland squad that pulled off the Grand Slam. It’s a swift progression that leaves him just a little bemused.
“It’s been strange, no doubt about that,” he smiles.
“If you had said it to me at the start of the season, I’d probably have laughed in your face. For me personally, it’s been great to get that experience in camp and be in the squad for the last two games. It’s nice to see what it takes to win a Grand Slam and the work that goes behind it.
“They all have Grand Slams now but they are guys you learn from and growing up guys you would have looked up to. You pinch yourself sometimes when you’re in there as you try to soak up what you can and learn off as many of them while you can.
“To get that look at what it takes to win a Grand Slam, there was so much that went into it and everyone played a part in it. It was awesome to see what it takes to go that next step and I’m very grateful that Joe gave me the opportunity to be in there.”
Very quickly, you realise that Arnold has his feet very much on the ground and hasn’t become carried away with his quickfire promotion.
“But from here on, for me it’s about focusing on Munster,” he stressed. “The next two weeks are massive and they are going to signify how the season goes come May.
“It’s going to be awesome for us having the lads coming back off the Grand Slam. They’re on top of the world, you know they’ll be coming back full of confidence, and that’s something sure to add to the team. It’s something I’m going to be looking forward to.”
Munster fans will be hoping that Arnold maintains the high standard he displayed when, after recovering from a series of frustrating injuries, his commitment and hard running and even harder tackling made him a key figure on his return. Now he is a seriously important member of the set-up as injuries continue to deprive the side of an outstanding centre (Chris Farrell), wing (Keith Earls) and out-half (Tyler Bleyendaal).
“It’s not easy with the pile of injuries but I think most teams in the league have injuries, except that with us it’s more senior guys going down. Probably more so than any other year.
“At the same time, it’s a great opportunity for younger guys to try and make that step up and see where they really are. We have had guys who stepped in before and they have managed to do a job. But this is the crunch time of the season and we have to get going this weekend.
“With all these injuries, I think I’m the exception to the rule. I had my bad luck last season. It’s one of those things that happen with every player. For us as a team, obviously we know we have to kick on from now but we can’t look any further than Scarlets this weekend.
“They beat us at home last season and they beat us in the final at the Aviva as well. They’re an awesome team and will be a massive challenge but one we’re very excited for as well.”
Arnold, a native of Redhill, Surrey and 22 early next month, is philosophical about the injuries that have hurt his career over the years, admitting that when the call comes for replacements to measure up it can be “tough to be ready”.
“As a rugby player, there’s rarely a time when you’re 100% fit. It’s so physical, you’re always going to be looking after something during the training week and making sure it’s 100% for the weekend so you can go full throttle. You have to rehab, you have to manage and play with it and get it right. It’s part of the game.”
Getting back to basics and Munster’s poor performance in Edinburgh he says: “The main focus this week has been guys taking a long, hard look at themselves both individually and as a team. We know ourselves what we put on display at the weekend wasn’t acceptable but we have the perfect chance this week against Scarlets of setting it straight.”