Pro-secession forces were doing similar stuff in the other border states at the time yet they were not blockaded, nor does their occurrence mean secession to have taken place. Thus the fact remains that The Lincoln declared war on Virginia before it seceded.
Both were within sight of Sumter
...but not within proximity of the battle. Try again.
But those actions of which you speak took place before the south initiated hostilities at Sumter. Once the confederate's hostile intent was established then there was no reason for President Lincoln to believe that Virginia would be any less hostile. He was within his power as President to establish the blockade to combat the rebellion.
...but not within proximity of the battle. Try again.
Both attacks were attempts by the confederate government to keep what they thought were supply efforts from reaching Sumter. Both were related to the confederate attempt to sieze something that didn't belong to them. The fact that the war did not start in either of those cases was due to the fact that the Union didn't want a war and held their fire. When the confederates fired directly on Sumter then there was no other choice.