Heat oven to 350°. Grease and flour two 9" x 5" x 2 1⁄2" loaf pans; set aside. In a medium bowl, whisk together flour, almond flour, and salt; set aside. In a large bowl, beat butter, sugar, and lemon zest until pale and fluffy, about 3 minutes. Add eggs one at a time, beating well after each addition, until smooth. Alternating, add flour mixture in 3 batches and milk in 2 batches, beginning and ending with flour mixture, and mix until just combined. Divide batter evenly between loaf pans and smooth tops; bake, rotating pans halfway through cooking, until golden brown and a toothpick inserted in the middle of each cake comes out clean, about 45 minutes.
While cakes bake, make the syrup: Bring sugar and juice to a boil in a 1-qt. saucepan over high heat, and cook, stirring, until sugar dissolves, about 1 minute; remove from heat. When cakes are finished baking, let cool for 10 minutes, and then, using a toothpick, poke as many holes as possible through each cake. Pour half the warm syrup over each cake, and allow cakes to cool completely in pans.
Make the glaze: In a medium bowl, whisk together sugar, juice, and zest until smooth. Remove cakes from pans and transfer to a serving platter. Drizzle half the glaze over each cooled cake and let glaze set before serving.