Bring a large pot of salted water to a boil and prepare a bowl of ice water. Blanch the broccoli for 1 minute in the boiling water. Plunge it into the ice water until completely cool and drain well.
In a small bowl, whisk together the yogurt, mayonnaise, oil and orange zest and juice. Season with salt and pepper.
In a large bowl, add the drained broccoli, carrots, raisins and onions. Pour over the dressing and toss to coat. Add the bacon and toss to coat again.