So your inference "While the blood of Christ is sufficient to save all men, it is, to borrow a word, only efficacious to the elect" is your own construct.
The New Testament says that in order to be saved one must (a) be baptized and (b) believe. This clearly shows that infant baptism was performed in the primtive Chruch because infants cannot believe. But, the NT also says that only those who do not believe will not be saved (i.e. baptism by itself does not save). [Mark 16:16]
So, Christ's redeeming Blood does not "work" for those who refuse God; yet God offered His Blood for ALL. In fact, He offers it until the very last breath of ours. Hello, what would it take for our lost brethren to comprehend that God would have all men saved? [1 Tim 2:4]
Sorry, kosta, I am using the word "efficacious" because we Catholics use it to define the difference between grace that is effective or responded to (efficacious), and one that is sufficient to accomplish the task that God wills, but the person DOES NOT respond to. It is a theological construct based on the De Fide belief that grace is not irresistible. (for example, 2 Cor 6:1)
It seems by the rest of your post that you and I (Catholics and Orthodox) agree on this. Sorry for the use of a non-Biblical word!
Brother in Christ