1 Thessalonians 1:4, how is the chronological order according to Calvinism? 1 Thessalonians 1:4 For we know, brothers loved by God, that he has
  chosen you




Before the creation:

A.
Because God love some people
that is why He choose these people

or.... 

B.
Because God choose some people
that is why He love these people



If there is an answer, I would like to have the verse also as the reason of the answer.
Since both the love of God for his own, and the election of God, in Christ, are an eternal matter, rather than a matter of time, I think that the question, in its present form, cannot be answered.

What is made clear in scripture is the following :


  I am crucified with Christ; nevertheless I live, yet not I but Christ lives in me; and the life which I now live in the flesh I live by the faith of the Son of God, who loved me and gave Himself for me. [Galatians 2:20, KJV.]


Three things are made clear :


The reason that the Son of God redeemed Paul was because the Son of God loved Paul prior to that redemption.
The redemption of Paul was not a corporate matter, but an individual matter. Paul was  not redeemed as one of an indiscriminate crowd, but as one personally known and loved.
The redemption of Paul occurred before Paul did any good works. Paul only 'now' lived by faith. Only 'now' after redemption is Paul crucified with Christ and walking in the Spirit.


Since the love is called the love 'of the Son of God' (not the love 'of Jesus') what is being drawn to the attention is the Divine and eternal love of Christ, in Deity, towards the man Paul.

If an eternal love, then a love that is not a matter of time, a love that had no temporal beginning and a love that cannot be separated (in terms of time) from other aspects of the Divine knowledge (that is to say foreknowledge) of the man Paul.


  Yea, I have loved thee with an everlasting love: therefore with lovingkindness have I drawn thee. [Jeremiah 31:3, KJV.]