When were the disciples saved? Some say when they were called, Come follow me. Some say not until after Christ ascended to heaven and then they received salvation and the Holy Ghost.

With the exception of Judas, the apostles were certainly saved during the lifetime of Christ, though I would not speculate as to the exact time. Consider the following:

Matthew 16:16-17 [16] And Simon Peter answered and said, Thou art the Christ, the Son of the living God. [17] And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.
See All... And Simon Peter answered and said, Thou art the Christ, the Son of the living God. And Jesus answered and said unto him, Blessed art thou, Simon Barjona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.

Peter believed in Christ as the Son of the living God and Jesus called him blessed for his faith and confession. Certainly this is a saved man. In another instance, many of the disciples of Jesus (not the twelve) were leaving as they found His teaching too difficult to accept. Here is the story in part:

John 6:66-69 [66] From that time many of his disciples went back, and walked no more with him. [67] Then said Jesus unto the twelve, Will ye also go away? [68] Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life. [69] And we believe and are sure that thou art that Christ, the Son of the living God.
See All... From that time many of his disciples went back, and walked no more with him. Then said Jesus unto the twelve, Will ye also go away? Then Simon Peter answered him, Lord, to whom shall we go? thou hast the words of eternal life. And we believe and are sure that thou art that Christ, the Son of the living God.

Here we see that the faith of Peter was common to the twelve (he says "we believe"). The further context of this passage shows that Judas is the particular exception to their faith. The eleven were certainly saved.

As to the receiving of the Holy Ghost, this was another matter. It is only in this Age of Grace that all believers are indwelled by the Holy Ghost. The apostles lived through this transition. Consider the following verses:

John 7:38-39 [38] He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water. [39] (But this spake he of the Spirit, which they that believe on him should receive: for the Holy Ghost was not yet given; because that Jesus was not yet glorified.)
See All... He that believeth on me, as the scripture hath said, out of his belly shall flow rivers of living water. (But this spake he of the Spirit, which they that believe on him should receive: for the Holy Ghost was not yet given; because that Jesus was not yet glorified.)

John 14:17Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.
See All... Even the Spirit of truth; whom the world cannot receive, because it seeth him not, neither knoweth him: but ye know him; for he dwelleth with you, and shall be in you.

Their salvation and their indwelling by the Holy Ghost occurred at two different times. On that the Bible is clear.