I don't even think about starting my arabs until 3.5. Then it's ground work. Some are just not ready. My old arab gelding was a holy terror until 5. Then he started to turn the corner. At 7 the best horse you could ask for. But seriously a raging a-hole until about 5. He would have huge temper tantrums, loose at liberty, and knock himself down. I remember watching him at 2 or 2.5 thinking; I've got to ride this thing. I bought him when he was 9 or 10 months old. I was the 3rd buyer. Not a splendid start. I'm not saying that he just magically turned the corner at 5. It was a long road. Consistent, sane work. What you do, has to make sense to the horse. Getting them worn out on a lunge before you ride is not the answer. You just get a fitter and fitter naughty horse. Teach them something while lunging. Submission is a good thing. You don't have to be mean, but you do have to be clear, and serious.