Preheat the oven to 350 degrees F. Grease bottom and sides of one 9 x 5-inch loaf pans; dust with flour, tapping out excess.
In a medium bowl, sift together flour, baking powder and salt; set aside.
In a large bowl, whisk together the yogurt, sugar, eggs, lemon zest, vanilla and oil. Slowly whisk the dry ingredients into the wet ingredients. In a separate bowl, mix the blueberries with the remaining tablespoon of flour, and fold them very gently into the batter.
Pour the batter into the prepared pan and bake 50 to 55 minutes, or until a toothpick inserted in the center of the loaf comes out clean. Let cool in the pans for 10 minutes before removing loaf to a wire rack on top of a baking sheet.
While the loaf is cooling, make the lemon syrup in a small saucepan over medium heat. Stir together the lemon juice and sugar until the sugar is completely dissolved. Once dissolved, continue to cook for 3 more minutes. Remove from the heat; set aside.
Use a toothpick to poke holes in the tops and sides of the warm loaf. Brush the top and sides of the loaf with the lemon syrup. Let the syrup soak into the cake and brush again. Let the cake cool completely.
To make the lemon glaze, in a small bowl, whisk together the confectioners’ sugar and 2-3 tablespoons of the lemon juice. The mixture should be thick but pourable. Add up to another tablespoon of lemon juice if the mixture is too stiff. Pour the lemon glaze over the top of each loaf and let it drip down the sides. Let the lemon glaze harden, about 15 minutes, before serving.